Syrian rebels walk next to a cannon that was captured with other weapons from the 46th Regiment base which was a major pillar of the government's force, near the northern city of Aleppo, Syria. / AP

by Tom A. Peter, Special for USA TODAY

by Tom A. Peter, Special for USA TODAY

ALEPPO, Syria -- The capture of a hydroelectric dam in northern Syria on Monday is the latest attempt by government opponents to cut off the military's supply lines around Aleppo and drive them out, say Syrian anti-government activists.

The Free Syrian Army (FSA) said its fighters overran the defenses of President Bashar Assad after several days of skirmishes to capture the Tishrin Dam on the Euphrates River, said the Syrian Observatory for Human Rights, an anti-Assad group based in England.

The dam is on a route that connects to Aleppo, a major city fought over for months by anti-Assad rebels and Assad loyalists.

"This is a major blow to the regime," said observatory spokesman Abdul-Rahman, describing the dam as a "strategic location."

Opposition fighters have made gains against Assad's forces in recent weeks. The FSA, a collection of revolutionaries and ex-members of Assad's military, says its fighters also forced out Assad troops from the Marj al-Sultan air base about 10 miles outside Damascus.

The claims could not be independently verified but, if true, the gains could be rolled back by reinforced Assad troops.

The seizure of the dam cuts off one major route for the Syrian army to resupply its troops that are pummeling rebels in Aleppo with heavy fire. However, the government can resupply by air as well.

As fighting drags on in Aleppo, those left behind in the city are struggling to maintain order. Looting has become a problem in a city where tens of thousands have fled their homes.

"Theft is a very big problem. All the families have left Aleppo, and their apartments are empty," says Rayan Awan, a neighborhood commander of the Revolutionary Security force that acts like a police force for the FSA. "Many people are stealing because there is no work."

Abdul Kareem Islami had been away from his home in Aleppo only two days to help his family resettle in a town near the border with Turkey away from the fighting when his neighbors called to tell him looters had broken into his home. He came back to find someone had stolen his refrigerator and washing machine.

Islami now keeps close watch of his apartment while working at his tile shop a few doors down. He says many others have been robbed.

"The situation with looting is better now, but it's very difficult because everything is very expensive here," he says, explaining why many have been pushed to looting.

The Revolutionary Security forces must also deal with members of the FSA who take advantage of the situation. It's not uncommon to find entire blocks that are almost completely deserted, a tempting target for some.

The FSA has taken control of the courts and prisons in Aleppo but given spotty governance in rebel-controlled areas, where there is often no official process for dealing with looters who are caught. Some culprits are driven to thievery out of desperation, so for them there is no need to seek justice, say fighters.

"The people stealing now are just simple people who need to stay alive," says Mahmoud Nadoum, an FSA commander. "We give them lessons about how they must behave in this situation and let them go."

Many people brought before the civilian administration of the Liwa Towheed, the largest rebel unit in Aleppo, are told to return what they've stolen. Some are even given a small amount of money to help.

Those caught a second time are sent to jail, though rebel fighters are treated more harshly.

"It's the duty of the (Free Syrian Army) to watch and protect the houses," says Abdul Qadir, a shoe salesman. "In every country, there are bad people who steal and now because of the war there are more people who come out to steal."

The conflict in Syria started in March 2011 as a peaceful demonstration movement against government abuses and in favor of democratic reforms. But Assad's attempt to crush the protests militarily and kill unarmed civilians prompted violent pushback from the protesters, turning the uprising into a bloody civil war.

More than 40,000 people have been killed by Assad loyalists, according to the Syrian activists. Hundreds of thousands of Syrians have fled to neighboring Lebanon, Jordan, Iraq and Turkey, according to the United Nations.